This invention relates to the twine wrapping mechanism commonly found in crop roll forming machines and, more particularly, to apparatus which will permit the overload protective device which protects the twine dispensers from damage to be easily reset in the driving position when the twine dispensers are subjected to a torque loading that exceeds a predetermined level.
Historically, it has been the custom to harvest forage crops by mowing the particular crop, letting it dry in the field, forming the dried crop material into windrows and passing a hay-baling machine over and along these windrows to form the crop material into rectangular bales. Recent practice has shown that the formation of crop material into large compact rolls, rather than rectangular bales as formerly done, permits the crop material to be deposited in roll form and left in fields for extended periods of time. The ability to leave these rolled bales in fields obviates the additional steps required in the traditional rectangular baling process of gathering the bales and transporting them to a storage area protected from the elements. This new technique of forming large round bales has created a baling system that can be conducted by one person. This is in marked contrast to the traditional practice of forming rectangular bales where the labor of several people was required to effect the cutting, drying, windrowing, baling, gathering and storing of the crop material.
Several methods of forming compact cylindrical rolls of crop material have evolved through the years. The most successful of these methods involves the forming of crop rolls by picking up a swath or windrow of material from the field and directing it onto a lower conveyor. This conveyor transports the material to a bale forming region where an upper apron or flight of belts, usually positioned above and adjacent the conveyor, moves in a suitable direction to rotate the crop material with which it is brought into contact. The increasing popularity of these crop roll forming machines has seen their use broaden from rolling wintering forage for livestock to rolling high protein crops, such as alfalfa, for dairy livestock. Therefore, these machines are the focal point of many ideas for developing both labor-saving and time-saving apparatus.
One of the areas to which attention has been directed is the area of wrapping the completed crop roll or bale with twine. Methods or techniques of applying twine to a completed crop roll have developed from a manually powered system through various electrical and hydraulically powered systems to finally an automatic twine wrapping system, which is mechanically driven without any operator input once the bale reaches a predetermined size. An example of this type of apparatus is found in U.S. Pat. No. 4,167,844 to Freimuth et al, dated Sept. 18, 1979. As shown and explained in this patent, there is achieved the saving of individual labor via the use of the automatically activated twine wrapping apparatus and the saving of time by the use of multiple twine dispensing tubes which move in a generally arcuate path across the periphery of the crop roll.
The development of this type of an automatic twine wrapping apparatus, as well as any of the other powered twine wrapping apparatus, such as electric motor or hydraulically driven variations, has required the use of some type of an overload protective device to prevent excessive damage from occurring to the twine wrapping apparatus under certain conditions. During operation occasionally rocks, broken portions of fencing and other large unyieldable obstacles are fed by the pickup into the roll forming area of the crop roll forming machine. When this infeed of ingestion occurs during the twine wrapping cycle, it is quite common for the twine dispensing tubes, which normally rotate about a fixed axis, to make contact with the obstruction. If the twine wrapping apparatus did not have some type of a breakway or overload protective device, severe damage would occur to the apparatus itself, as well as to the drive system for the twine wrapping apparatus.
One variation of a breakaway or overload protective apparatus that has been employed successfully is that shown in U.S. Pat. No. 4,072,095 to Campbell et al, issued Feb. 7, 1978. This type of breakaway device disengages the dispensing tubes or twine dispensers from the drive system above a previously calculated torque load before damage can occur to either the dispensers or the drives.
Once the overload protective device or breakaway has interrupted the transmission of power from the driving means to the twine dispensing tubes, the twine wrapping apparatus is inoperative until the breakaway is reset to the power transmitting position. In the type of apparatus shown and described in U.S. Pat. No. 4,167,844, this resetting of the apparatus into the power transmitting condition or position can be extremely difficult since the two dispensing tubes must be moved simultaneously while the connecting links in the drives and retained in suitable positions to permit the breakaway to be reset. This is a burdensome operation for one person and usually requires more than one person to accomplish. The disadvantage of this type of a design is obvious when it is realized that crop roll forming machines are designed to be and essentially function as one person hay or crop gathering systems. More frequently than not, an extra individual is not readily available to assist in resetting the twine wrapping apparatus.
The foregoing problems are solved in the design of the machine comprising the present invention by providing alignment means in a twine wrapping apparatus to permit the overload protective apparatus or breakaway to be repositioned in the power transmitting position by retaining at least a portion of the drives in a fixed position in a manner that is easily accomplished by a single individual.